// Copyright (C) 2018 Storj Labs, Inc.
// See LICENSE for copying information.

package pointerdb

import (
	"context"

	"go.uber.org/zap"

	"storj.io/storj/pkg/overlay"
	"storj.io/storj/pkg/pb"
	"storj.io/storj/pkg/provider"
	"storj.io/storj/pkg/utils"
	"storj.io/storj/storage"
	"storj.io/storj/storage/boltdb"
	"storj.io/storj/storage/postgreskv"
	"storj.io/storj/storage/storelogger"
)

// CtxKeyPointerdb Used as pointerdb key
type CtxKeyPointerdb int

const (
	// BoltPointerBucket is the string representing the bucket used for `PointerEntries` in BoltDB
	BoltPointerBucket                 = "pointers"
	ctxKey            CtxKeyPointerdb = iota
)

// Config is a configuration struct that is everything you need to start a
// PointerDB responsibility
type Config struct {
	DatabaseURL          string `help:"the database connection string to use" default:"bolt://$CONFDIR/pointerdb.db"`
	MinRemoteSegmentSize int    `default:"1240" help:"minimum remote segment size"`
	MaxInlineSegmentSize int    `default:"8000" help:"maximum inline segment size"`
	Overlay              bool   `default:"false" help:"toggle flag if overlay is enabled"`
}

func newKeyValueStore(dbURLString string) (db storage.KeyValueStore, err error) {
	dburl, err := utils.ParseURL(dbURLString)
	if err != nil {
		return nil, err
	}
	if dburl.Scheme == "bolt" {
		db, err = boltdb.New(dburl.Path, BoltPointerBucket)
	} else if dburl.Scheme == "postgresql" || dburl.Scheme == "postgres" {
		db, err = postgreskv.New(dbURLString)
	} else {
		err = Error.New("unsupported db scheme: %s", dburl.Scheme)
	}
	return db, err
}

// Run implements the provider.Responsibility interface
func (c Config) Run(ctx context.Context, server *provider.Provider) error {
	db, err := newKeyValueStore(c.DatabaseURL)
	if err != nil {
		return err
	}
	defer func() { _ = db.Close() }()

	cache := overlay.LoadFromContext(ctx)
	dblogged := storelogger.New(zap.L(), db)
	pb.RegisterPointerDBServer(server.GRPC(), NewServer(dblogged, cache, zap.L(), c, server.Identity()))

	return server.Run(ctx)
}

// LoadFromContext gives access to the pointerdb server from the context, or returns nil
func LoadFromContext(ctx context.Context) *Server {
	if v, ok := ctx.Value(ctxKey).(*Server); ok {
		return v
	}
	return nil
}